Switchboard cord-circuits for fire-alarm telephone systems.



J. EHICKSON.

SWITCHBOARD CORD CIRCUITS FOR FIRE ALARM TELEPHONE SYSTEMS.

APPUCATION FILED FEB-25.1914.

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Patented May 15, 1917.

4 I I 15 A H 1 nurrnn srarns RMEENT JOHN ERICKSON, OF CHICAGQ, ILLINOIS, ASSIGNGR, BY 1VLE$NE ASSIGNIVLENTS, TO ROCHESTER H. ROGERS, OF ROCHESTER, NETV YGRK.

SWITCHBOABD CORD-CIRCUITS FOE FIRE-ALARM TELEPHCNE SYSTEMS.

Application filed February 25, 1914.

1 '0 (M6 whom it may concern.

Be it known that 1, JOHN ERICKSON, of Chicago, county of Cook, State of Illinois, have invented certain new and useful Improvements in Switchboard Gordfiircuits for FireAlarm Telephone Systems; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification, and to the reference-numerals marked thereon.

My present invention relates particularly to fire alarm telephone systems, that is, a

telephone system in connection with which call boXes or signaling apparatus is located at a subscribers station, by means of which a code number or signal may be despatched to the central oifice, or exchange, and from the latter transmitted to the fire department headquarters over an out-going circuit to which the in-coming subscribers circuit is connected by the central oiiice operators cord circuits. In this connection, my invention has for its object to provide a simple and novel arrangement of the operators cord circuits and the fire alarm trunk circuit whereby incoming impulses, due to a change of potential in the current on the subscribers circuit caused by the operation the alarm signaling mechanism, will be repeated to the recording apparatus located at the fire department headquarters.

Again, stating my invention more espeeially, it will be understood. that it is my obiect to provide a switch-board cord circuit in which the strands of the answering and calling ends are provided with inductive windings or impedance coils and condensers, so that impulses oi current occurring in the circuit completed over the answering cord will be repeated or reproduced in the strands of the calling cord and the outgoing circuit to which it is connected. The operating circuit with which the calling cord operates is provided with a polarized magnetic device comprising windings which are alter nately energized and deenergized accord ing to the direction of the How of current reproduced periodically when the strands of the calling cord are connected. to said circuit. To these and other ends the invention consists in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel fea- Speeification of Letters Patent.

Patented May 15, 1%17.

Serial No. 821,096.

tures being pointed out in the "claims at the end of the specification.

In the drawings:

The figure is a diagrammatic illustration showing the central otfice apparatus, a subscribers line circuit and a fire alarm trunk and out-going operating circuit.

In illustrating my present invention I have shown the in-coming subscribers telephone circuit as comprising the wires 1 and 2 which terminate in the springs 1, 2 of the switch-board jack A. At the subscribers station there is arranged in addition to the usual telephone set any suitable form of impulse transmitting mechanism, such that indicated by A, comprising a movable -member or code wheel having teeth as shown, which serve to alternately open and close a pair of contacts 1 2 and thus serve to vary the potential of the current flowing in the subscribers circuit, the number and rapidity of the impulses transmitted corresponding to the size and number of the teeth of the wheel. Also associated with the subscribers circuit, but located at the central office, are the usual line and cut-elf relays by means of which the operators attention is attracted to in-coming calls.

A special out-going circuit leads to the fire alarm headquarters, for operating the alarm bell and recording apparatus, but the impulses of current transmitted over such c'rcuit are controlled in part by a polarized magnetic device located at the central ofiice and arranged in a trunk circuit connected in multiple to switchboard jackslocated one at each operators position. In the illustration, this trunk circuit is indicated as comprising conductors 3 and 4 extending from the jacks B, B where they terminate in the springs a I), to one terminal of each of the windings T Ci of the polarized repeating relay T. The other terminals of these coils are connected to the positive and negaive sides of the central office battery F by the wires t and respectively. These ties to the battery leads are not made for the purpose of obtaining current but to complete the loop in the inductive circuit, which is made when the plug of the calling cord is inserted in one of the jacks B, as will he further explained hereinafter.

The coils T T are polarized by a permanent magnet and pivoted above them is a rocking armature T one end of which serves to open and close a pair of contacts 16 t which represent the terminals of the out-going circuit wires 5 and 6 leading to the fire department headquarters, over which current is supplied from the battery F to operate the signal bell S and the recorder or punch It, said bell and punch being of any desired construction, illustration and details of which are, for this reason, omitted.

The type of switchboard cord circuits shown in the drawing constructed in accordance with my invention are inductively connected, preferably by means of primary and secondary induction windings, in such a way that when the main or incoming circuit, composed of-the subscribers telephone line and the answering cord strands is closed, a magnetic field is built up in the primary windings, and a current impulse is induced, also when the primary circuit is opened an impulse of current is induced in the secondary windings, these impulses flowing over the strands of the calling cord and the trunk circuit comprising the polarized. electro-magnetic opcrating mechanism. The impulses flowing from the secondary windings upon the completing of the main ci'. uit are of one polarity and those flowing when the main circuit is opened are of the oppos te polarity, consequently the armature T 1s rocked in opposite directions upon each make and break occurring in the main circuit.

The cord circuit consists of the answering plug C and'the calling plug G, each comprising the tip and ring contacts 0,c and g, 9 The strands of the answering cord, indicated'by' 7 and 8, lead fromthe tip and ring contacts 0 0 respectively, to the opposite poles of the battery or source of current supply F. In these strands 7 and 8, I include the primary windings of the induction coils J and J with which are associated the secondary windings J and J in the strands 9 and 10 of the calling cord which terminates respectively in the tip and ring contacts g, g of the plug G. These coils are preferably formed on a closed core J.

One strand of each cord leads through the customary supervising relays K, K in addition to which other devices and the necessary circuits'for their operation .are provided, but as all of thesethings constitute well known standard apparatus and do not in anywise affect the operation of the apparatus previously described, they have been omitted from the illustration, but it .will be understood that they may be employed in practice when desired.

In describing the operation of the apparatus in detail itWillbe assumedi'that the subscriberhas pulled or set h-is'fire alarm apparatusinto operation,- this'closes the contacts 1 and 2 signaling the central oflice operator in the usual manner by. means of the line and pilot lamps. The operator then inserts the plug C of the answering cord in the subscribers line jack A and by reason of the intermittent opening and closing of the circuit, which is then going on, accompanied by a signal identifiedas a fire alarm signal, she immediately inserts the plug G of the calling cord in one of the jacks B of the fire alarm trunk. In practice two or more of these trunks would be employed so that in the event the one first tested by the operator proves busy she will immediately insert the plug G in the jack of another trunk.

When the connection with the subscribers circuit is made with the answering cord, current flows thereover as follows: Battery F, coil J, strand 7, tip 0, spring 1*, line 1, contacts 1 2*, line wire 2, spring 2, ring 0 strand 8, relay K, coil J to battery. By the insertion of the plug G in one. of the jacks B a separate loop or circuit is completed through each of the coils of the polarized electro-magnetic operating device-T, as-will be seen by tracing the following leads. Starting now from one terminal of the coil. J tracing the strand 9 to the tip g, spring 6 conductor .3, coil- T and returning by wire t to the other terminal of the coil J Similarly, starting from one terminal of the coil J it will be seen that the circuit leads through the strand 10 to the ring 9 spring 6 conductor 4t, coil T thence by the return wire 25 to the other extremity of the coil J. The direction of the turns of the windings J and J and their respective magnet coils T, 'T are such that the proper polarity of the latter is always maintained, so that the rocking of the armature T under the influence of the magnetism developed in said coils will occur in proper unison with the-changes of potential. of the current in the main circuit eilected by the operation of the fire alarm box B.

I claim as my invention:

1. The combination with a main circuit, a source of current supply therefor and means for varying the potential of said current comprising an alarm impulse despatching mechanism, of an inductive circuit in which current impulses are generated by fluctuations in the potential in said main circuit, a polarized magnet coil inthe inductive circuit and devices operated by the magnetism developed in said coil lfor transmitting impulses equivalent to the originally despatched impulses. V

2. The combination with a main circuit, a source of current supply'therefor and means for varying" the potential of said current comprising an .alarm impulse despatching mechanism, ott two inductive circuits Bin which current impulses are generated by variations in the potential in said main circuit, two polarized magnet coils, one located in each of said inductive circuits and devices ope 'ated by the magnetism developed in said coils for recording the impulses originally despatched.

3. The combination with a main circuit, means for varying the potential of the flow of current therein and a polarized electromagnet device comprising magnet coils, of a separate circuit for each magnet coil, means associated with the main circuit and with each of said magnet circuits for inductively generating current in the latter upon the occurrence of fluctuations of current in the main circuit.

l. The combination with a telephone answering cord circuit, of a calling cord circuit, a pair of inductive circuits one side of each constituting one side of said calling cord circuit, means for varying the potential of the current flow in said answering cord circuit, and means whereby an induced current is generated in said inductive circuits by the variation of the potential of the current flow in the answering cord circuit.

5. In a telephone fire alarm system, the combination with a subscribers circuit provided with means for varying the potential of current flowing therein comprising a code signal impulse despatching mechanism, and a separate fire alarm circuit provided with a polarized magnetic operating device, of switchboard mechanism for connecting said circuits whereby the code impulses may be reproduced in the alarm circuit comprising answering and calling cords each having tip and ring strands provided with inductive windings and a source of current supply connected to the tip and ring strands of the answering cord.

6. In a telephone fire alarm system, the combination with a subscribers circuit having a call box provided with means for varying the potential of current flowing in said circuit, a central oiiice switchboard answer ing and calling cord circuits, and a source of current supply connect-ed to the answering cord, of a fire alarm circuit comprising two conductors adapted to be connected with the calling cord, means for inducing impulses of current in the circuit thus formed upon variations of current occurring in the subscribers circuit and polarized magnetic operating devices having coils arranged one in each of said conductors.

'7. In a telephone fire alarm system, the combination with subscribers line circuits, an alarm trunk circuit, an out-going alarm circuit for cooperation with said trunk, and means for transmitting current impulses over the subscribers circuit, of central oflice answering and calling cord circuits conductively disconnected and inductively connected, a source of current supply for said cords, and an electro-magnetically operated device in the trunk circuit actuated by the current impulses induced in the calling cord to close and open said out-going alarm circuit,

8-. In a telephone system, the combination with an answering cord circuit, of a calling cord circuit, a subscribers line circuit, means on said subscribers lino circuit for varying the potential of the current fiow therein, means associated with both cord circuits for inductively generating current in the calling cord circuit, a trunk circuit for connection with the calling cord circuit, and devices in said trunk circuit adapted to be influenced by the current so induced in the calling cord circuit to close and open the trunk circuit beyond said devices.

9. In a telephone fire alarm system, the combination with a subscribers line circuit and means for producing code impulses of current therein, a fire alarm trunk circuit, a polarized electro-magnetically operated device therein having an armature and devices controlled thereby, an out-going alarm circuit associated with said devices, of separate answering and calling cord circuits for connecting the subscribers line circuit with the fire alarm trunk circuit and means for inductively connecting said cord circuits for causing impulses of current produced in the answering cord to be induced in the calling cord and repeated in the polarized el.ectro magnetic device for closing and opening said out-going alarm circuit.

10. In a telephone fire alarm system, the combination with a subscribers line circuit having means for producing impulses of current therein, and a central o'llice answering cord circuit adapted to be connected to said line circuit, of a polarized electromagnetic repeater having magnet coils and a movable armature, a separate circuit for each of said coils both ofsaid circuits inductively associated with the answering cord to actuate the repeater and means controlled by the movement of said armature.

11. In a telephone fire alarm system, the combination with a central. exchange, a subscribers line circuit having means for producing impulses of current therein, and an answering cord circuit, comprising two conductors, of a repeater having two electromagnet coils, a pair of conductors each forming a separate circuit for one of said coils and means connecting each of said circuits inductively with the conductors of the answering cord.

12. In a telephone fire alarm system, the combination with a central exchange, a sub scribers line circuit having means for pr0- ducing impulses of current therein, and an answering cord circuit, of a repeater having two electro-magnet coils and an armature, a pair of conductors each forming a closed circuit for one of said coils, and means associated with the cord circuit and the pair of conductors for inducing impulses of current in the latter corresponding to the impulses produced in the answering cord.

13. In a telephone fire alarm system, the combination with a central oflice, a subscribers line circuit having means for producing impulses of current thereon and an answering cord circuit having two primary windings therein, of a repeater having two electro-magnet coils, a pair of conductors each forming a circuit for one of the coils, and a secondary winding in each of. said conductors associated with the primary windings.

141. In a telephone fire alarm system, the combination with a subscribers line provided with means for producing impulses therein, and a central oflice switchboard having an answering cord circuit and a calling cord circuit, of a polarized electro-magnetic repeater having a movable armature, and a circuit for each coil of said repeater inductively associated with the answering cord circuit to actuate the armature of said repeater in one direction for the current flow through one circuit and in the opposite direction for the current flow in the other circuit.

15. In a telephone fire alarm system, the combination with a subscribers line circuit, impulse transmitting mechanism connected to said line circuit, and a central office switchboard including an answering cord circuit adapted to be connected to the said line circuit, a calling cord circuit and an alarm trunk circuit arranged to be connccted with the calling cord circuit, of means for inductively generating the impulses of the line and answering cord circuits in the calling cord and alarm trunk circuits, a polarized electromagnetic repeater in said alarm trunk circuit arranged to be influenced by the change of flow of the current in the calling cord and alarm circuits and an out-going circuit arranged to be closed and opened by the action of said repeater.

16. In a telephone fire alarm system, the combination with a subscribers line circuit, impulse transmitting mechanism connected to said line circuit, and a central oflice switchboard including an answering cord circuit adapted to be connected to the said line circuit, a calling cord circuit, and a normally open alarm trunk circult arranged to be connected with the calling cord circuit and closed thereby, of means for inductively transmitting the impulses from the line and answering cord circuits to the calling cord and alarm trunk circuits, a normally open circuit, and a polarized electromagnetic repeater in the alarm trunk circuit, including an armature, and arranged to change the movement of said armature dependent upon the direction of current flow in the calling cord and alarm trunk circuits to close and open said normally open circuit.

17 In a telephone fire alarm system, the combination with a subscribers line circuit and a central oflice answering and calling cord circuits, of an alarm trunk arranged to be associated with the calling cord circuit, means for transmitting current impulses over the subscribers line and answering cord circuits, means for inducing impulses of current in the calling cord and alarm trunk circuits corresponding to the impulses produced in the answering cord and line circuits, a polarized electro-magnetic repeater adapted to be influenced by the impulses induced in the calling cord and alarm trunk circuits, and a recording circuit arranged to be opened and closed by said polarized repeater.

18. The combination with a main circuit, a source of current supply therefor, and means for varying the potential of said cur rent, of an inductive circuit in which current impulses are generated by fluctuations in the potential in said main circuit, a polarized magnetic coil in the inductive circuit, devices operated by the magnetism developed in said coil, and an out-going circuit to be closed and opened by the operation of said devices.

19. The combination with the main circuit, a source of current supply therefor, and means for varying the potential of said current, of two inductive circuits, an inductive coil in each inductive circuit whereby impulses are generated therein by variations in the potential in said main circuit, two polarized magnetic coils, one located in each of said inductive circuits, and devices operated by the magnetism developed in said coils for reproducing and recording the current impulses aforesaid.

JOHN ERIGKSON.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). C. 

